Cutting head for use in a dry shaving apparatus having an oval shape movable cutter



1963 J. TIMMERMAN ET Al. 3,078,571

CUTTING HEAD FOR USE IN A DRY SHAVING APPARATUS HAVING v AN OVAL SHAPE MOVABLE CUTTER Filed Feb. 5, 1960 INVENTOR HENRIGUS J. DRIESSEN ANNE KOOISTRA GERRIT STARRE BY JAN TIMMERMAN CUTTENG HEAD FQR USE IN A DRY SHAVING APPARATUS HAVING AN OVAL SHAPE MOV- ABLE QUTTER Jan Timmerman and Anne Kooistra, Eindhoven, and Gerrit Starre and Henrietta .losef Driessen, Drachten, Netherlands, assignors to North American Philips Company, ind, New York, N.Y., a corporation of Delaware Filed Feb. 3, 196b, Ser. No. 6,478 Claims priority, application Netherlands Feb. 2.0, 1959 3 Claims. (Ci. 39-43) This invention relates to improvements in or relating to cutting heads for use in a dry shaving apparatus co-m prising an apertured shear plate and a rotatably arranged cutting member co-operating herewith and centered in a running groove of the shear plate, a dry shaving apparatus comprising such a cutting head and a cutting memher and shear plate for use in such a cutting head.

It is already known to center, in a cutting head for use in a dry shaving apparatus, comprising an apertured shear plate and a rotatable cutting member co-operating herewith, the cutting member in a running groove of the shear plate in order to prevent the cutting member and the shear plate abrading each other. As a matter of course, a small amount of play in a radial direction of the cutting member is required in this case, in order to minimize the friction between the cutting member and the shear plate.

During operation of this known cutting head a sharp piercing noise may sometimes occur abruptly. Extensive research has proved that the cutting member tends to roll off its centering, which gives rise to considerable centrifugal force. In the period when the cutting member moves toward the rolling-oif position, a slip occurs between the cutting member and its centering, which produces the aforesaid sound. It has been found that the considerable centrifugal force and the slip of the cutting member in its centering are the essential factors producing this sound and a heavy frictional force.

The invention has for its object to avoid the objectionable piercing noise explained above.

In accordance with the invention either the centering wall of the running groove or the envelope of the centering sides of the cutting member is shaped in a form deviating from that of a circle, for example in an oval form.

Thus the rolling-off phenomenon and hence the abrupt occurrence of the piercing noise are avoided.

A practical, simple embodiment of the invention consists in that in a cutting head in which the centering of the cutting member takes place by means of the sides of the feet provided with cutting edges, all sides located on one side of a center line of the cutting member are ground ed on the inner side.

In this manner hair and the like is prevented from accumulating in the running groove, which might cause the cutting member to be jammed. The running groove is scraped clean by the cutting member.

The sides are preferably ground off to an extent such that the cutting member can touch simultaneously both the inner wall and the outer wall of the running groove of the shear plate.

In this manner the running groove can be scraped clean throughout its width, while the cause of the rolling-01f phenomenon is avoided most effectively.

The invention also relates to a separate cutting member and a separate shear plate.

The invention will be described more fully with reference to the accompanying drawing.

3,978,571 Patented Feb. 26, 1983 FIG. 1 is a sectional view taken on an axis of rotation of a cutting head together with its drive;

FIGS. 2 and 3 are a bottom view of a cutting head according to the invention; and

FIG. 4 is a bottom of a cutting member according to the invention.

A shear plate 1 is provided with slots 2 and forms a running groove 3, in which a cutting member 4 is centered. The sides 5 on the inner side ofthe cutting edges 6 are located on feet 7 of the cutting member 4 thereby providing the centering. The cutting member 4 is driven by a shaft 8, which is provided at the top end with a flattened part 9, located in a corresponding opening 10 of the cutting member 4. The shaft 9 is provided at the bottom end with a square 13, which is capable of moving in an axial direction in a gear wheel 14, to which it is secured in the direction of rotation. A spring 15 holds the cutting member 4 against the shear plate 1.

In a known embodiment of the cutting head shown in FIG. 1 the co-operation between the sides 5 of the cutting member 4 and the Wall 16 of the shear plate 1 provides the centering. Both the side 5 and the wall 16 are then shaped in the form of clear circle cylinders.

As shown in FIG. 2 the wall 16 is shaped in a form deviating from that of a circle and indicated by the broken line 17. Owing to the shape of the wall 16 the sides 18 and 19 can run along the outer wall 20 of the groove, so that the rolling-off phenomenon on one wall is prevented.

According to FIG. 3 the sides 22 and 23 located on the same side of the center line 24 are ground off. The sides 25 and 26 are therefore capable of engaging the outer wall 2i) of the running groove 3, so that the latter can be scraped clean throughout its width.

FIG. 4 shows the outlines 27 and 28 of the centering cutting edges. The outline 28 is shaped in a form deviating from that of a circle 29 owing to grinding-01f of the sides 22 and 23.

What is claimed is:

1. A cutting head for use in a dry shaver comprising an apertured shear plate having a running groove, a rotatable cutting member coacting therewith and centered in said running groove, said shear plate being prm vided with centering walls, the sides of said cutting member adjacent to said centering walls being shaped in a substantially oval form.

2. A cutting head for use in a dry shaver comprising an apertured shear plate having a running groove, a rotatable cutting member coacting therewith and centered in said running groove, said cutting member having feet with sides provided with cutting edges wherein all sides located on one side of the center line of said cutting member are ground off on the inner side and said sides of said cutting member being substantially oval in shape.

3. A cutting head for use in a dry shaver as claimed in claim 2 wherein said sides are ground off to a configuration such that the cutting member is capable of engaging simultaneously both the inner wall and the outer wall of the running groove of said shear plate.

References Cited in the file of this patent UNITED STATES PATENTS 2,229,971 Hammerling Ian. 28, 1941 2,283,865 Cohen May 19, 1942 2,337,391 Horowitz et al Dec. 21, 1943 2,339,831 Andersen Jan. 25, 1944 

1. A CUTTING HEAD FOR USE IN A DRY SHAVER COMPRISING AN APERTURED SHEAR PLATE HAVING A RUNNING GROOVE, A ROTATABLE CUTTING MEMBER COACTING THEREWITH AND CENTERED IN SAID RUNNING GROOVE, SAID SHEAR PLATE BEING PROVIDED WITH CENTERING WALLS, THE SIDES OF SAID CUTTING MEMBER ADJACENT TO SAID CENTERING WALLS BEING SHAPED IN A SUBSTANTIALLY OVAL FORM. 